1. Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing a semiconductor device.
2. Description of the Related Art
An existing semiconductor device includes a wiring made of aluminum or an aluminum alloy and formed on a substrate, an anti-reflection film made of titanium nitride and formed on the wiring, and an oxide film formed on the anti-reflection film, and a pad portion which exposes the wiring is formed at a place where an opening portion formed in the oxide film and an opening portion formed in the anti-reflection film overlap with each other in plan view.
In a semiconductor device of having such a structure, titanium nitride forming the anti-reflection film is sometimes corroded in a portion surrounding the opening portion by a long-term reliability test that involves bias application under a high-temperature and high-humidity environment, abbreviated as THB (Temperature Humidity Bias).
To solve this problem, a semiconductor device has been proposed in which titanium nitride forming the anti-reflection film is not exposed in the opening portion.
For example, in Japanese Patent No. 5443827, there is proposed a semiconductor device including: a first surface protection film with a first opening portion formed above a pad; and a second surface protection film formed on the pad and the first surface protection film to have a second opening portion above the pad, in which the pad includes a first conductor film and an anti-reflection film formed on the first conductor film, the second opening portion is contained in an inner region of the first opening portion, and the anti-reflection film is removed from the inner region of the first opening portion.
However, in the method described in Japanese Patent No. 5443827, it is required to perform a photolithography step twice to process the opening for exposing the pad, which increases the number of steps.
In addition, in a semiconductor device of the related art, particularly one in which a silicon oxide film is formed on an anti-reflection film made of titanium nitride, and the titanium nitride and the silicon oxide film are exposed in an opening portion for exposing a pad, the anti-reflection film may change into titanium oxide due to the long-term reliability test with bias under a high-temperature and high-humidity environment (THB), resulting in a possible impairment of the external appearance.